dt-bindings: display: rockchip: dw-hdmi: fix ports description

Current port description doesn't cover all possible cases. It currently
expects one single port with two endpoints.

When the HDMI connector is described in the device tree there can be two
ports, first one going to the VOP and the second one going to the connector.

Also on SoCs which only have a single VOP there will be only one
endpoint instead of two.

This patch addresses both issues. With this there can either be a single
port ("port") , or two of them ("port@0", "port@1") when the connector
is also in the device tree. Also the first or only port can either have
one endpoint ("endpoint") for single VOP SoCs or two ("endpoint@0",
"endpoint@1") for dual VOP SoCs.

Signed-off-by: Sascha Hauer <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Tested-by: Michael Riesch <[e-mail]>
Signed-off-by: Heiko Stuebner <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml

···
   ports:
     $ref: /schemas/graph.yaml#/properties/ports
 
-    properties:
-      port:
-        $ref: /schemas/graph.yaml#/$defs/port-base
-        unevaluatedProperties: false
+    patternProperties:
+      "^port(@0)?$":
+        $ref: /schemas/graph.yaml#/properties/port
         description: Input of the DWC HDMI TX
-
         properties:
+          endpoint:
+            description: Connection to the VOP
           endpoint@0:
-            $ref: /schemas/graph.yaml#/properties/endpoint
             description: Connection to the VOPB
-
           endpoint@1:
-            $ref: /schemas/graph.yaml#/properties/endpoint
             description: Connection to the VOPL
-
-        required:
-          - endpoint@0
-          - endpoint@1
-
-    required:
-      - port
+    properties:
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: Output of the DWC HDMI TX
 
   rockchip,grf:
     $ref: /schemas/types.yaml#/definitions/phandle